1. Field of the Invention
The present invention relates generally to motor vehicles, and in particular the present invention relates to an impact absorbing airbag module.
2. Description of Related Art
In order to meet current safety regulations, most modern motor vehicles include some form of supplemental restraint system. These systems often include an airbag. Airbags are generally contained in a housing with a suitable inflator. This complete system is sometimes referred to as an airbag module. During an impact, the inflator quickly releases compressed gasses to inflate the airbag, which is deployed by the gasses. In the deployed condition, airbags are designed to cushion the impact experienced by the driver or passengers.
While airbag systems can be helpful during some types of collisions, there are some other collisions where the motor vehicle may have difficulty passing certain government mandated crash test requirements because passengers or drivers may impact the airbag module itself. These collisions generally occur at low speeds or low impact impulses where airbags are not designed to deploy. In these types of collisions, occupant impact with airbag modules can cause compliance problems with government mandated crash tests. To avoid this, the following airbag systems have been proposed.
U.S. Pat. No. 6,312,008 to Neag and assigned to DaimlerChrysler Corporation is directed to an energy absorbing bracket for an airbag system. Neag discloses a side airbag that is deployed with generally less force than a frontal airbag. The airbag module of Neag includes an energy absorption bracket 40 with upper downstanding leg 46 and lower downstanding leg 48. These downstanding legs are designed to bend when the airbag module experiences an impact.
U.S. Pat. No. 6,296,277 to Bittinger et al. and assigned to Chrysler Corporation is directed to a passenger restraint system with a crush zone. The '277 patent teaches crush zones 32 and 34 disposed on end caps 16 that are designed to absorb the impact of a passenger's knees during a collision. However, the end caps 16 of Bittinger are not part of the airbag.
U.S. Pat. No. 6,279,942 to Bossenmaier et al. and assigned to DaimlerChrysler Corporation is directed to a deformable air bag housing. The '942 patent provides a good background discussion of deformable air bag housings and notes that prior deformable air bag housings presented sharp corners or edges after deformation. These sharp corners could tear or snag a deploying air bag. The '942 patent discloses a deformable airbag housing that is designed to minimize damage to the airbag during inflation. To accomplish this, the '942 patent discloses a slot 15 that runs nearly the entire width of side cover 8. Slot 15 divides side cover 8 into two parts 16 and 17 as shown in cross-sectional views A-A and B-B. Upper part 16 includes a slightly bent lower edge that allows upper part 16 to slide outward of lower part 17 as side cover 8 deforms.
The following patents disclose air bag modules with collapsible side walls. Generally, some feature or provision is provided so that a portion of the side wall is weakened and assists in promoting deformation of the side wall at that weakened region.
U.S. Pat. No. 5,791,684 to Repp et al. and assigned to Morton International and Chrysler Corporation teaches an air bag canister with grooves of various cross-sectional shapes. U.S. Pat. No. 5,533,747 to Rose and assigned to Morton International discloses the use of slots 40 to provide a weakened region. Rose also teaches a “zigzag” shaped side walls 28 and 30. U.S. Pat. No. 5,405,163 to Amamori et al. and assigned to Tanaka Corporation teaches a side wall that includes stress concentration portions 61 to assist the air bag container in deforming. Finally, referring to FIGS. 16 and 17, related art air bag inflator module 2000, designed to use a cylindrical inflator 2008, includes walls 2002 and 2004 with perforations 2006. These perforations 2006 can assist air bag inflator module 2000 in deforming.
While the related art teaches a variety of features that can be used to reduce the severity of an impact with an airbag module, none of the references teaches an airbag module that is easy to design and manufacture, that is easy to tune and configure for different motor vehicles, different locations and different types of collisions, and an airbag module that can reduce the possibility of tearing an airbag during deployment.